Petrogenetic history of lava flows from the Casitas Shield in the Southern Volcanic Zone, Chile

Relatively few studies have investigated the geochemistry of the Descabezado Grande-Cerro Azul (DGCA) volcanic complex, located in the Southern Volcanic Zone (SVZ) of the Chilean Andes. Lava samples were collected in stratigraphic order from vertical stacks of flows exposed along the walls of steep canyons incised in the flanks of the Casitas shield of Cerro Azul. In order to determine dominant petrogenetic processes and identify changes in the composition of the magmatic system over time, this project obtained mineral analyses using x-ray fluorescence (XRF) as well as textural analyses of petrographic thin sections using scanning electron microscopy (SEM). Analyses of the younger lavas were found to be composed mostly of basalts with some basaltic andesite compositions, results that are more primitive than older lavas previously sampled in this section and throughout the Southern Volcanic Zone

Bedrock geology of the East Andover quadrangle, Maine

Maine Geological Survey, Open-File Map 22-17.https://digitalmaine.com/mgs_maps/3160/thumbnail.jp

Bedrock geology of the East Andover quadrangle, Maine

Maine Geological Survey, Open-File Map 22-17.https://digitalmaine.com/mgs_maps/3160/thumbnail.jp